# MIME Types — Configuring Media Types for Web Servers Correctly > Reference for MIME types (media types) on web servers: extension-to-Content-Type, charset, nosniff and configuration in Apache and nginx. Source: https://www.jpkc.com/db/en/cheatsheets/web-servers/mime-types/ A MIME type — also called a media type — tells the browser what to do with the bytes of a response. Unlike on a file system, the web does not rely on the file extension: the `Content-Type` header sent by the server decides the behaviour. A wrong type breaks rendering: web fonts fail to load, JavaScript modules are blocked, stylesheets are ignored. Add `charset=utf-8` to define the character encoding for text types, and set `X-Content-Type-Options: nosniff` to stop browsers from guessing the type — an important defence against MIME-sniffing attacks. This reference lists the common media types by category and shows how to map them correctly in Apache and nginx. ## Text Types `text/html` — HTML documents. The primary content type for web pages. Default charset is US-ASCII; always specify UTF-8. ```bash Content-Type: text/html; charset=UTF-8 ``` `text/css` — Cascading Style Sheets. Required for to be applied by browsers. ```bash — server must send text/css ``` `text/javascript` — JavaScript code. The official IANA type (replaces application/javascript and application/x-javascript). ```bash Content-Type: text/javascript — used for ``` `application/xml` — XML-encoded data for APIs and data exchange. Use text/xml only if the content is human-readable. ```bash Content-Type: application/xml — SOAP, Atom feeds, config APIs ``` `application/graphql` — GraphQL query string. Informal but widely used. Alternatively send as application/json with a query field. ```bash Content-Type: application/graphql — POST /graphql with raw query body ``` `application/x-www-form-urlencoded` — URL-encoded form data (key=value&key2=value2). Default encoding for HTML forms without file uploads. ```bash

without enctype — sends application/x-www-form-urlencoded ``` `application/octet-stream` — Arbitrary binary data / unknown type. Browsers treat it as a download. The safe fallback for unknown files. ```bash Content-Type: application/octet-stream Content-Disposition: attachment; filename=data.bin ``` `application/pdf` — Adobe Portable Document Format (.pdf). Browsers usually display PDFs inline using their built-in viewer. ```bash Content-Type: application/pdf — add Content-Disposition: attachment to force download ``` `application/yaml` — YAML Ain't Markup Language. RFC 9512 (2024). Used for OpenAPI/Swagger specs and config files. ```bash Content-Type: application/yaml — OpenAPI spec endpoint ``` `application/wasm` — WebAssembly binary module. Required for .wasm files to be compiled efficiently by browsers (RFC). ```bash Content-Type: application/wasm — required for streaming compilation with WebAssembly.instantiateStreaming() ``` `application/manifest+json` — Web App Manifest (.webmanifest). Defines PWA metadata: name, icons, theme color, display mode. ```bash — server must serve this type ``` `application/rss+xml` — RSS feed format for syndication. Extension: .rss. Browsers and feed readers detect it automatically. ```bash ``` `application/atom+xml` — Atom syndication feed. RFC 4287. More standardized than RSS, used by many modern feed sources. ```bash ``` ## Application — Archives & Compressed Files `application/zip` — ZIP archive format. The most common archive type on the web. Extension: .zip. ```bash Content-Type: application/zip — download.zip ``` `application/gzip` — gzip-compressed data (.gz). Different from Content-Encoding: gzip — this is the file itself. ```bash Content-Type: application/gzip — backup.tar.gz ``` `application/x-bzip2` — bzip2-compressed archive (.bz2). Better compression than gzip, common on Linux distributions. ```bash Content-Type: application/x-bzip2 — archive.tar.bz2 ``` `application/x-xz` — XZ compressed data (.xz). High compression ratio, used for Linux kernel and distro packages. ```bash Content-Type: application/x-xz — package.tar.xz ``` `application/x-7z-compressed` — 7-Zip archive format (.7z). Very high compression, common on Windows. ```bash Content-Type: application/x-7z-compressed — archive.7z ``` `application/x-rar-compressed` — RAR archive format (.rar). Proprietary format, common for large software distributions. ```bash Content-Type: application/x-rar-compressed — archive.rar ``` `application/x-tar` — TAR archive (uncompressed, .tar). Usually combined with gzip (.tar.gz) or bzip2 (.tar.bz2). ```bash Content-Type: application/x-tar — files.tar ``` `application/java-archive` — Java Archive (.jar). A ZIP file containing Java class files and resources. ```bash Content-Type: application/java-archive — app.jar ``` ## Application — Office & Document Formats `application/vnd.openxmlformats-officedocument.wordprocessingml.document` — Microsoft Word document (.docx). OOXML format used by Word 2007 and later. ```bash Content-Type: application/vnd.openxmlformats-officedocument.wordprocessingml.document ``` `application/vnd.openxmlformats-officedocument.spreadsheetml.sheet` — Microsoft Excel spreadsheet (.xlsx). OOXML format used by Excel 2007 and later. ```bash Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet ``` `application/vnd.openxmlformats-officedocument.presentationml.presentation` — Microsoft PowerPoint presentation (.pptx). OOXML format used by PowerPoint 2007 and later. ```bash Content-Type: application/vnd.openxmlformats-officedocument.presentationml.presentation ``` `application/vnd.ms-excel` — Legacy Microsoft Excel format (.xls). Binary format from Excel 97–2003. ```bash Content-Type: application/vnd.ms-excel — legacy.xls ``` `application/vnd.oasis.opendocument.text` — OpenDocument Text format (.odt). Used by LibreOffice Writer. ```bash Content-Type: application/vnd.oasis.opendocument.text — document.odt ``` `application/vnd.oasis.opendocument.spreadsheet` — OpenDocument Spreadsheet format (.ods). Used by LibreOffice Calc. ```bash Content-Type: application/vnd.oasis.opendocument.spreadsheet — sheet.ods ``` `application/epub+zip` — EPUB e-book format (.epub). A ZIP file containing HTML, CSS, images, and metadata. ```bash Content-Type: application/epub+zip — book.epub ``` `application/rtf` — Rich Text Format (.rtf). Cross-platform document format supported by most word processors. ```bash Content-Type: application/rtf — document.rtf ``` ## Image Types — Classic Raster Formats `image/jpeg` — JPEG/JPG — lossy compression for photos (.jpg, .jpeg). Widely supported, no transparency. Best for photos. ```bash

— server sends image/jpeg; quality vs. file size tradeoff ``` `image/png` — PNG — lossless compression with full alpha transparency (.png). Best for graphics, logos, screenshots. ```bash

— server sends image/png; larger than JPEG for photos ``` `image/gif` — GIF — 256 colors, lossless, supports animation (.gif). Largely replaced by WebP for animation. ```bash

— still widely used for short looping animations ``` `image/bmp` — BMP — Windows Bitmap, uncompressed raster format (.bmp). Very large files, no web use. ```bash Rarely used on the web. Used internally by Windows for icons and wallpapers. ``` `image/tiff` — TIFF — high-quality lossless format for print and archiving (.tif, .tiff). Not supported natively in browsers. ```bash Used in print workflows, medical imaging, and professional photography. ``` `image/x-icon` — ICO — Windows icon format (.ico). Used for browser favicons. Supports multiple sizes in one file. ```bash ``` `image/svg+xml` — SVG — Scalable Vector Graphics (.svg). XML-based, resolution-independent, fully scriptable. Ideal for icons and logos. ```bash

or inline

``` `image/avif` — AVIF — AV1 Image File Format (.avif). Excellent compression (better than WebP), HDR, wide color gamut, alpha. Supported in Chrome 85+, Firefox 93+, Safari 16+. ```bash

``` `image/jxl` — JPEG XL — next-gen format with lossless JPEG recompression, HDR, wide gamut, animation (.jxl). Superior quality/size. Safari 17.4+ (macOS/iOS). Chrome/Firefox support behind flags or dropped. ```bash Accept: image/jxl, image/avif, image/webp, image/jpeg — server-side content negotiation ``` `image/heic` — HEIC — High Efficiency Image Container (.heic). Apple's default camera format (iPhone iOS 11+). Based on HEVC/H.265. Limited browser support; usually converted server-side. ```bash iPhone uploads: convert HEIC → JPEG/WebP/AVIF before serving on the web. ``` `image/heif` — HEIF — High Efficiency Image Format (.heif). The container standard that HEIC is based on. Same limitations as HEIC for web use. ```bash Content-Type: image/heif — HEIC uses the same MIME type family; use heic for Apple files. ``` `image/apng` — APNG — Animated PNG (.apng, .png). Supports full-color animation with alpha, unlike GIF. Supported in all modern browsers. ```bash

— full 24-bit color with transparency, unlike GIF's 256 colors ``` `image/jp2` — JPEG 2000 (.jp2) — wavelet-based compression, lossless mode, transparency. Only natively supported in Safari (macOS/iOS). Not recommended for general web use. ```bash Safari on macOS accepts image/jp2. Other browsers need JS decode libraries. ``` ## Audio Types `audio/mpeg` — MP3 audio (.mp3). The most universally supported audio format. Uses MPEG-1/2 Audio Layer III compression. ```bash

``` `audio/ogg` — Ogg Vorbis or Opus audio in an Ogg container (.ogg, .oga). Open, patent-free. Good Firefox/Chrome support. ```bash ``` `audio/opus` — Opus audio codec (.opus). Open format optimized for speech and music, low latency. Excellent for WebRTC and streaming. ```bash — best codec for real-time audio (WebRTC) ``` `audio/wav` — WAV — uncompressed PCM audio (.wav). Very large files, no compression. Used for lossless archiving and as audio source in Web Audio API. ```bash — high quality but large file size ``` `audio/webm` — WebM container with Vorbis or Opus audio (.weba, .webm). Open format backed by Google. ```bash ``` `audio/aac` — AAC — Advanced Audio Coding (.aac, .m4a). Successor to MP3 with better quality at same bitrate. Native on iOS/Safari. ```bash — commonly used on Apple devices ``` `audio/flac` — FLAC — Free Lossless Audio Codec (.flac). Perfect audio reproduction, ~50% of WAV size. Supported in modern browsers. ```bash — lossless streaming for audiophiles ``` `audio/mp4` — MP4 container with audio-only content (.m4a, .m4b). Typically contains AAC or ALAC audio. ```bash Content-Type: audio/mp4 — Apple audiobooks (.m4b), iTunes purchases (.m4a) ``` ## Video Types `video/mp4` — MPEG-4 Part 14 (.mp4, .m4v). The most widely supported video format on the web. Usually contains H.264/AVC video and AAC audio. ```bash

``` `video/webm` — WebM — Google's open video format (.webm). Contains VP8/VP9/AV1 video with Vorbis/Opus audio. Excellent compression. ```bash — smaller than H.264 MP4 ``` `video/ogg` — Ogg container with Theora video (.ogv). Open, patent-free. Mostly replaced by WebM in modern browsers. ```bash ``` `video/mpeg` — MPEG-1 or MPEG-2 video (.mpeg, .mpg). Legacy format from the 1990s. Limited browser support. ```bash Content-Type: video/mpeg — DVD and broadcast video; use MP4 for web delivery ``` `video/quicktime` — Apple QuickTime video (.mov). Typically contains H.264 or ProRes. Good support in Safari; use MP4 for cross-browser. ```bash Content-Type: video/quicktime — iMovie/Final Cut exports; transcode to MP4 for web ``` `video/x-msvideo` — AVI — Audio Video Interleave (.avi). Legacy Microsoft format. No native browser support; must be converted. ```bash Content-Type: video/x-msvideo — convert to MP4 or WebM before web delivery ``` `video/x-matroska` — Matroska / MKV container (.mkv). Popular for high-quality video with multiple audio/subtitle tracks. Limited browser support. ```bash Content-Type: video/x-matroska — use for downloads; transcode to MP4/WebM for streaming ``` `video/mp4; codecs=av01` — AV1 video has no standalone file MIME type; it is served inside an MP4 (`video/mp4`) or WebM (`video/webm`) container with `codecs=av01…`. Open, royalty-free, ~50% better compression than H.264. Chrome 70+, Firefox 67+, Safari 17+. ```bash — best compression ratio ``` ## Font Types `font/woff2` — Web Open Font Format 2 (.woff2). The recommended modern web font format. Brotli compression, ~30% smaller than WOFF. Supported by all modern browsers. ```bash @font-face { src: url('font.woff2') format('woff2'); } — use this as primary format ``` `font/woff` — Web Open Font Format 1 (.woff). Fallback for older browsers (IE9+). zlib compression. Larger than WOFF2. ```bash @font-face { src: url('font.woff2') format('woff2'), url('font.woff') format('woff'); } ``` `font/ttf` — TrueType Font (.ttf). Uncompressed outline font. Used as fallback and natively on Android/iOS. ```bash @font-face { src: url('font.ttf') format('truetype'); } — fallback for very old browsers ``` `font/otf` — OpenType Font (.otf). Supports advanced typography (ligatures, small caps, alternates). Uncompressed like TTF. ```bash @font-face { src: url('font.otf') format('opentype'); } — preferred for advanced typography ``` `font/collection` — Font Collection (.ttc, .otc). A single file containing multiple font faces (e.g., CJK collections). ```bash Content-Type: font/collection — NotoSansCJK.ttc containing Regular, Bold, Italic ``` ## Multipart & Form Data `multipart/form-data` — Used for HTML form uploads containing files. Required for . Includes a boundary delimiter. ```bash — Content-Type: multipart/form-data; boundary=----XYZ ``` `multipart/mixed` — Multiple body parts of different types. Used in email (attachments) and some batch API responses. ```bash MIME email with text/plain body + application/pdf attachment — multipart/mixed ``` `multipart/alternative` — Multiple alternative representations of the same content. Used in email for text/plain + text/html versions. ```bash Email multipart/alternative: text/plain for old clients, text/html for modern clients ``` `multipart/byteranges` — Server response containing multiple byte ranges (for HTTP 206 multi-range responses). ```bash GET /file.pdf with Range: bytes=0-100,200-300 → 206 multipart/byteranges response ``` ## Tips & HTTP Header Usage `Content-Type: type/subtype; charset=UTF-8` — Sent by server to tell the client what the response body is. The charset parameter is critical for text types. ```bash Content-Type: application/json — no charset needed (JSON is always UTF-8 per RFC 8259) ``` `Accept: image/avif,image/webp,image/jpeg,*/*` — Sent by client to declare which types it accepts. Use for content negotiation to serve the best format. ```bash Chrome sends: Accept: image/avif,image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8 ``` `Content-Disposition: attachment; filename="file.pdf"` — Forces a download dialog regardless of Content-Type. Use filename* for UTF-8 filenames (RFC 5987). ```bash Content-Disposition: attachment; filename*=UTF-8''Daten%C3%BCbersicht.csv ``` `X-Content-Type-Options: nosniff` — Prevents browsers from MIME-sniffing (guessing the type). Always set this header to avoid XSS via type confusion. ```bash Without nosniff, a browser may execute an HTML file served as text/plain as HTML. ``` `type/* wildcard in Accept header` — Use wildcards to accept any subtype. image/* accepts all images, */* accepts everything (with lowest priority). ```bash Accept: application/json, text/*, */*;q=0.1 — prefer JSON, then any text, then anything ``` `q-factor (quality value) in Accept` — Numeric priority from 0 to 1 (default 1.0). Tells the server which format is preferred when multiple types are listed. ```bash Accept: text/html, application/json;q=0.9, */*;q=0.8 — prefer HTML, then JSON ``` `Apache: AddType / TypesConfig` — Configure MIME types in Apache via .htaccess or httpd.conf. Use AddType for one-off additions. ```bash AddType image/avif .avif AddType image/webp .webp AddType font/woff2 .woff2 ``` `Nginx: types { } block in mime.types` — Nginx reads /etc/nginx/mime.types. Add missing types in the server or http block using types { } override. ```bash types { image/avif avif; image/webp webp; font/woff2 woff2; application/wasm wasm; } ``` `PHP: header('Content-Type: ...')` — Set the response content type in PHP before any output. Overrides the server's default. ```bash header('Content-Type: application/json; charset=UTF-8'); echo json_encode($data); ``` ## Conclusion The right MIME type is not a detail — it decides whether browsers render your content correctly or block it. Always set `charset=utf-8` for text types, serve modern formats like `image/avif` and `font/woff2` with their proper types, and enable `X-Content-Type-Options: nosniff` to stop MIME sniffing. Maintain missing mappings centrally in your web server's `mime.types` rather than scattering them across individual `AddType` lines. ## Further Reading - [IANA Media Types](https://www.iana.org/assignments/media-types/media-types.xhtml) – the official registry of all registered media types - [MDN: MIME types](https://developer.mozilla.org/en-US/docs/Web/HTTP/Guides/MIME_types) – overview and the most important types for web development ## Related Commands - [apache](https://www.jpkc.com/db/en/cheatsheets/web-servers/apache/) – configure the web server, MIME types via AddType and mime.types - [caddy](https://www.jpkc.com/db/en/cheatsheets/web-servers/caddy/) – modern web server with automatic HTTPS - [certbot](https://www.jpkc.com/db/en/cheatsheets/web-servers/certbot/) – manage TLS certificates from Let's Encrypt